Earthworms help cleanse dairy wastewater

Fresno State has turned to a group of very efficient workers to help clean up wastewater on the campus dairy.

Red earthworms now play a big role in the effort to solve water quality challenges. They squirm when you interrupt their meal.

The worms dig in and feast on wood shavings soaked in wastewater from cow manure.

Sanjar Taromi is the chief marketing officer for BioFiltro. He explained, "The wood shavings absorb a lot of the organic contaminants within the wastewater. The worms then eat that material depositing their castings."

The Chilean based company relies on worms to do their dirty work for the pilot project at Fresno State.

Taromi said, "We're also taking analysis of wastewater to show to reductions in key indicators like nitrates and nitrogen, phosphates."

Taromi added the campus dairy uses over 25,000 gallons of water each day. This system filters about 15 percent of the wastewater. "Water is turned on and it comes and flushes the lanes down and carries the manure down to the solid separation basins."

The water which came out of the cow stalls was a murky dark brown. After the bio-filtration process the water was a lighter brown color but Taroma says that was due to the wood shavings. As the worms turn they produce a cleaner, recycled product.

Taroma said, "You have irrigation water that now you can use with drip irrigation, with center pivots."

Dairy wastewater is normally only used for flood irrigation on crops used for feed.